MT3 vs R8 spindle taper

[Eyecon]

Hello Friends,
So things escalated quickly today and I went from wondering about a cx605 mill to ordering a PM-25MV clone from a local eBay seller. Initially I could find the MT3 spindle taper version but after contacting the seller they said they can get the R8 version by mid December. Soon after placing the order, seller told me it would actually take much longer and I’d have to wait until mid Feb due pandemic related delays in China. Regardless of the intent/backstory, the MT3 version is supposedly in stock in Canada. I know Morse taper is really designed as a self holding taper so might be annoying to take out tools or holders each time. Opinions? Do I wait for the R8 in 3 months or go for the MT3?

 

[Crankit]

I would suggest having a look around at the availability of MT3 tooling, I was looking at a decent small mill a few years ago which was using MT3 and there wasn't a lot around at the time. R8 is night and day difference, personally I would wait for that R8 model.

Cheers,

Wayne

 

[DavidR8]

I have MT 3 taper on my mill and have no problem getting tooling. I use an ER32 collet chuck on a MT3 arbor, and I have an MT3 collet which I use with TTS-style tool holders. I bought a straight shank Criterion boring head and a straight shank face mill which I use with the MT3 collet.

 

[Eyecon]

I have MT 3 taper on my mill and have no problem getting tooling. I use an ER32 collet chuck on a MT3 arbor, and I have an MT3 collet which I use with TTS-style tool holders. I bought a straight shank Criterion boring head and a straight shank face mill which I use with the MT3 collet.

Very interesting, my primary use would be with an ER collect chuck as I already have the collets and an mt3-er32 that I use on my lathe. I want to be able to quickly switch between the er collet(s) and my Haimer for which I was hoping to have a fixed tool holder(TTS style or something similar). Do you have any issues with MT3 getting stuck? Also would you mind sharing some details about the MT3 collet to TTS style holders? The reason I’m interested in a fixed tool length holder is because of the eventual CNC conversion. I’d really like to avoid having to probe tool length each time if I don’t have to(unfortunately I currently have to do so in my ER20 routers)

 

[Former Member]

R8 as it has a spline to prevent rotation, depending on the CNC configuration this interface will become your weak link. As an example 1/2" endmill full width cut 0.050 depth at 20IPM puts a lot of load on everything.

 

[Susquatch]

Do I wait for the R8 in 3 months or go for the MT3?

I'd wait for the R8. I have an MT3 in my big Mill Drill. It does the job. Still LOTS of tooling options out there. I have an R8 in my knee mill. I like it better! You can't really depend on the index pin in it to stop rotation. That should be done by achieving the correct torque. Lots of R8s out there with broken pins. Torque it correctly and it won't happen - knock on wood......

I think the big difference is that R8 is a near self releasing taper vs MT3 - way less thumping. Much easier on the spindle and much easier on the machinist. Mine certainly is....

Supposedly R8 is also more precise. Or so they say. I don't believe it. Perhaps it's just that as you move up the food chain there is more R8 than MT3.

Edit - the pins on most R8 spindles is usually easy to replace so don't let that scare you. Better to have it than not.

 

[Susquatch]

Soon after placing the order, seller told me it would actually take much longer and I’d have to wait until mid Feb due pandemic related delays in China. Regardless of the intent/backstory, the

Frankly, this scares me. Although all this stuff comes from China today, the shifting sellers story gives me the creeps.

Some folks on here would say skip the middle man and buy direct from China.

Others would say go to a higher line re-seller like Precision Mathews.

Still others would say buy from Busy Bee, King, or Grizzly.

My own preference would be to buy a good used one.

Regardless, we are all interested in following how your buy goes. Please keep us informed.

 

[6.5 Fan]

You already have some MT3 tooling that is used on the lathe, so i would go that route. I have MT3 on the lathe and mill they sit close to one another and i use the same tooling on both machines. Just my point of view, less stuff to buy, spend more on cutters.

 

[Eyecon]

Frankly, this scares me. Although all this stuff comes from China today, the shifting sellers story gives me the creeps.

Some folks on here would say skip the middle man and buy direct from China.

Others would say go to a higher line re-seller like Precision Mathews.

Still others would say buy from Busy Bee, King, or Grizzly.

My own preference would be to buy a good used one.

Regardless, we are all interested in following how your buy goes. Please keep us informed.

I would go with a PM If they had presence in Canada. The idea of paying 400-500 dollars in shipping and some ridiculous customs clearing fees and dealing with all that from US or China is what led me to look at the Craftex cx605 in the first place and then this eBay seller offering free shipping. I’ll take a look at what King has.

 

[Eyecon]

Thanks everyone for the replies. So the only similarly sized/spec’d option in Canada that I could find that doesn’t cost too much to ship is a king PM25 clone from KMS tools. It’s R8 but geared spindle and brushed single phase AC…maybe the motor is not an issue but I’d rather have a less popular taper than gears that are potentially plastic. Open to other suggestions but it looks like i may go with the in stock mt3 version from that eBay seller as it’s also about 350 cad cheaper not including the tax reduction.

 

[Former Member]

In all my years if using an R8 I've never broken the pin (knock on wood) but I also torque the draw bar correctly as @Susquatch recommends.

I have spun a MT on an occasion or two.

 

[Eyecon]

In all my years if using an R8 I've never broken the pin (knock on wood) but I also torque the draw bar correctly as @Susquatch recommends.

I have spun a MT on an occasion or two.

I’m honestly not sure the r8 spindle configuration on this clone even takes pins. I get the point of course

 

[Susquatch]

You already have some MT3 tooling that is used on the lathe, so i would go that route. I have MT3 on the lathe and mill they sit close to one another and i use the same tooling on both machines. Just my point of view, less stuff to buy, spend more on cutters.

This is an absolutely excellent point. Tooling cost is almost always more than the machine cost for most of us. Might also provide some redundancy as both prolly come with a drill chuck. One will probably be better than the other. Heck you might even find yourself swapping!

If you go this way, keep an eye on the drawbar thread when you order stuff. The MT3 drawbar thread is not always the same on all MT3 tooling. This has caught me a few times and then I had to deal with the return hassle. I prolly should have just made another drawbar.

 

[Eyecon]

Yes lm almost 100% the mt3 will be a metric M12 drawbar vs 3/8-16 which I guess is standard for MT3 in North America. I’m also finding native Mt3 tools like boring heads, face mills, fly cutters in MT3 and they cost the same as the R8 versions. Also collets on MT3 almost cost the same as R8 although there might be slight more buying options for R8. I understand the slippage concern but l doubt this cheap clone will have a keyed R8 spindle so I’m not really seeing the point. TTS exists for both R8 and MT3 as well which could be a plus for fixed tool size cnc setup. Also I don’t believe the power drawbar mechanism for either type of spindle will be any different.

Again, I’m super new to this but it feels like it the MT3 options will be equally good especially that I can take delivery sooner and save 400 cad in price difference and tax

 

[Eyecon]

One last thing I should mention is that I pan to mainly use ER collets at the beginning to share tools and collets with my CNC routers…other the figure out the Haimer situation, I’m not really planning on using the drawbar for tool changes unless I make a dedicated mount for the Haimer vs chucking it in the er20 or er32 collets

 

[Susquatch]

I understand the slippage concern but l doubt this cheap clone will have a keyed R8 spindle so I’m not really seeing the point.

I'd bet big bucks it does. The only ones I've ever seen that didn't were actually broken, not missing.

I don't think the main purpose of the pin is to stop slippage. That is the job of the taper. If you torque it properly, the pin shouldn't be required and shouldn't be breaking either.

I think the pin is mostly there to hold the adapter while you tighten the drawbar. It's way easier than putting your finger in there to hold it. I've also seen a few people spin the taper in instead of turning the drawbar. Not a practice that I recommend. Of course, once the taper engages, it's not an issue anymore.

FWIW, I like the pin.

 

[Eyecon]

Oh I see, that’s very interesting and at least given the price difference and wait time maybe make me feel a little better about the mt3 version. Like I said I’m very new to the world of small mills but given what everyone said and what’s available in terms of Asian tools, it feels like I should really save the money and go with the in-stock mt3 version.

 

[phaxtris]

Just a thought, but if you go r8 all of your tooling will swap over to your next larger mill

 

[DavidR8]

Very interesting, my primary use would be with an ER collect chuck as I already have the collets and an mt3-er32 that I use on my lathe. I want to be able to quickly switch between the er collet(s) and my Haimer for which I was hoping to have a fixed tool holder(TTS style or something similar). Do you have any issues with MT3 getting stuck? Also would you mind sharing some details about the MT3 collet to TTS style holders? The reason I’m interested in a fixed tool length holder is because of the eventual CNC conversion. I’d really like to avoid having to probe tool length each time if I don’t have to(unfortunately I currently have to do so in my ER20 routers)

I have never had the MT3 collet get stuck or be hard to remove.
The TTS holders are just as they are sold with a 3/4" straight shank. They slip right into my 3/4" collet no problem.

 

[Eyecon]

Just a thought, but if you go r8 all of your tooling will swap over to your next larger mill

I think if I go larger it will be a VMC with bt or iso tappers. I really do appreciate the advice but I don’t want to wait 3 months( basically also have 2700 CAD on hold) to get started on an entry level mill because of the spindle taper. I also hope that if I really want to, I’d find the R8 spindle arbor and bearings do the replacement if I absolutely regret the mt3